The Deformation and Recrystallization of an Alloy containing Two Phases

Abstract

The deformation and recrystallization of a duplex brass containing 60 per cent. copper and 40 per cent. zinc has been studied using microscopic and X-ray methods. In compression and tensile tests the α phase commences to deform plastically at a lower stress than the β phase, and even after heavy deformations, it is deformed more severely. Which of the two phases starts to recrystallize first on annealing depends on the rate of cooling of the alloy prior to deformation.

In the quenched wires the α phase commences to recrystallize about 100°C. below the β phase, whereas in the slowly cooled wires the β phase commences to recrystallize before the a phase. In the former case, the β recrystallizes at a lower temperature, the smaller the amount of β present, i.e. the lower the temperature of quenching. It has been shown that the order-disorder transformation is responsible for the difference of behaviour of the slowly cooled wires from that of the quenched wires.

Microscopic examination shows that the α phase starts to recrystallize at random whereas the β phase tends to nucleate at the boundaries between the two phases. The experiments indicate that it is not possible to conclude that a phase has suffered more severe deformation because it commences to recrystallize at a lower temperature.